Thieno[3,4-b]thiophene and thieno[3,4-b]furan are known compounds that are useful as monomers in the preparation of intrinsically conducting polymers. A known method of preparing thieno[3,4-b]thiophene requires an expensive starting material 3,4-dibromothiophene. Furthermore, this process does not allow for the easy derivatization of the 2 position of the thieno[3,4-b]thiophene, thereby limiting the flexibility of the process.
There remains a continuing need in the art for new, inexpensive, and facile processes to prepare thieno[3,4-b]thiophene, thieno[3,4-b]furan, and related compounds. Furthermore, there is a continuing need for a facile process to prepare derivatives of these fused heterocycles.